Moscow is a terrifying city for drivers. So what if a car doesn't have one?

Chaotic roads, bad weather and reckless habits make the Russian capital one of the worst to drive, and its quest to build an autonomous car uniquely challenging In certain sunny climes, self-driving cars are multiplying. Dressed in signature spinning sensors, the vehicles putter along roads in California, Arizona and Nevada, hoovering up data that will one day make them smart enough to run without humans. Besides perennial sunshine, those places share other common traits: wide, well-manicured ro...